Table of Contents
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4.
Uneven density (front side dark)
5.
Uneven density (front side light)
Cause
Step
Primary
1
corona wire
height
Developing
2
assembly
Dirt on the
3
scanner
Pre-exposure
4
lamp unit
Developing
5
assembly
Corona as-
sembly and
copy paper
COPYRIGHT © 1999 CANON INC.
Checks
Does the image quality improve after the
basic adjustment procedure is followed?
Is the spacer roller of the developing as-
sembly pressing against the photosensitive
drum?
Does the image improve after the scanning
lamp, reflectors, side reflectors, lens and
dust-proofing glass are cleaned?
Do the pre-exposure lamps go ON during
copying?
Is the surface of the developing cylinder
coated uniformly with toner?
CANON NP6320 REV.0 DEC. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 10 TROUBLESHOOTING
YES/
Action
NO
YES
End.
NO
Check the pressure ap-
plying mechanism of the
developing assembly.
YES
End.
NO
1. Replace the pre-expo-
sure lamp unit.
2. Replace the DC con-
troller PCB.
NO
1. Clean the edge of the
blade of the develop-
ing assembly.
2. If the problem is in the
black developing as-
sembly, wipe the sur-
face of the developing
cylinder with a dry
cloth.
YES
1. Clean all the corona
wires once more; then,
recheck the position of
each corona wire.
2. Try changing the copy
paper.
10-29
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Chapters
Table of Contents
Troubleshooting
